no it depends what do you study.
Marijuana IS addictive and the molecular mechanism of addiction is already described. It is similar to all other types of addictions. read here:
Molecular mechanisms of cannabinoid addiction
Current Opinion in Neurobiology
Volume 23, Issue 4, August 2013, Pages 487–492
23/4 Addiction
Molecular mechanisms of cannabinoid addiction
Cannabis is the world's most widely used illicit substance, with an estimated number of 119–224 million users worldwide. In recent years we assisted to an increased effort aimed to individuate the brain circuits underlying cannabis addiction and dependence. Similarly to other drugs of abuse, repeated exposure to cannabinoids causes brain neuroadaptations that persist long after drug effects, contribute to the negative affective states during withdrawal, and ultimately facilitate relapse. Recently, considerable progress has been made in understanding the cellular and molecular consequences of prolonged cannabis use, among which is the identification of specific set of transcriptional regulations that develop differently after chronic cannabinoids and in the abstinent brain.
The expression of central cannabinoid (CB1) receptors in tyrosine hydroxylase (TH) containing neurones was demonstrated. Co-localisation was present in different brain areas responsible for reward-related mechanisms. The immunohistochemical investigations have shown that co-localisation is present in parts of mesolimbic-mesocortical dopaminergic system like nucleus accumbens (Nacb), ventral tegmental area (VTA), in the striatum, pyriform cortex, respectively. The results suggest a functional role of CB1 receptors in cannabis addiction by acting directly on reward-related structures.